:root {
    /* Light theme defaults */
    --bg: #f5f5fa;
    --bg-elevated: #ffffff;
    --bg-elevated-soft: #f8f8ff;
    --border-subtle: rgba(15, 23, 42, 0.07);
    --border-strong: rgba(15, 23, 42, 0.12);
    --text: #0f172a;
    --text-soft: #64748b;
    --accent: #2563eb;
    --accent-soft: rgba(37, 99, 235, 0.1);
    --accent-strong: #1d4ed8;
    --danger: #ef4444;
    --danger-soft: rgba(239, 68, 68, 0.1);
    --radius-lg: 18px;
    --radius-md: 12px;
    --radius-pill: 999px;
    --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.12);
    --shadow-subtle: 0 10px 30px rgba(15, 23, 42, 0.06);
    --transition-fast: 150ms ease-out;
    --transition-med: 200ms ease;
}

[data-theme="light"] {
    color-scheme: light;
}

[data-theme="dark"] {
    color-scheme: dark;
    --bg: #020617;
    --bg-elevated: #020617;
    --bg-elevated-soft: #020617;
    --border-subtle: rgba(148, 163, 184, 0.32);
    --border-strong: rgba(148, 163, 184, 0.6);
    --text: #e5e7eb;
    --text-soft: #94a3b8;
    --accent: #60a5fa;
    --accent-soft: rgba(96, 165, 250, 0.16);
    --accent-strong: #3b82f6;
    --danger: #f97373;
    --danger-soft: rgba(248, 113, 113, 0.18);
    --shadow-soft: 0 22px 60px rgba(15, 23, 42, 0.8);
    --shadow-subtle: 0 16px 40px rgba(15, 23, 42, 0.8);
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

body {
    min-height: 100vh;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", sans-serif;
    background: radial-gradient(circle at top left, #dbeafe 0, transparent 50%), 
                radial-gradient(circle at bottom right, #fef3c7 0, transparent 55%), var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
}

.app-shell {
    max-width: 1120px;
    margin: 32px auto 48px;
    padding: 0 16px;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 16px 20px;
    border-radius: var(--radius-lg);
    background: linear-gradient(120deg, rgba(15, 23, 42, 0.96), rgba(30, 64, 175, 0.96));
    color: #e5e7eb;
    box-shadow: var(--shadow-soft);
    position: sticky;
    top: 16px;
    z-index: 10;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-mark {
    width: 36px;
    height: 36px;
    border-radius: 12px;
    background: radial-gradient(circle at 30% 20%, #bbf7d0, #22c55e);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #052e16;
    font-weight: 700;
    box-shadow: 0 0 0 1px rgba(15, 23, 42, 0.6), 0 14px 30px rgba(22, 163, 74, 0.8);
}

.brand-text h1 {
    margin: 0 0 2px;
    font-size: 1.2rem;
    letter-spacing: 0.04em;
}

.brand-text p {
    margin: 0;
    font-size: 0.8rem;
    opacity: 0.75;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

.icon-button {
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.26);
    background: rgba(15, 23, 42, 0.4);
    color: inherit;
    padding: 6px 10px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background var(--transition-fast), border-color var(--transition-fast),
                transform var(--transition-fast), box-shadow var(--transition-fast);
    box-shadow: 0 10px 25px rgba(15, 23, 42, 0.8);
}

.icon-button:hover {
    border-color: rgba(209, 213, 219, 0.8);
    background: rgba(15, 23, 42, 0.9);
    transform: translateY(-1px);
    box-shadow: 0 14px 35px rgba(15, 23, 42, 0.95);
}

.icon-sun,
.icon-moon {
    width: 18px;
    height: 18px;
    border-radius: 999px;
    border: 2px solid currentColor;
    position: relative;
}

.icon-sun::before {
    content: "";
    position: absolute;
    inset: 1px;
    border-radius: inherit;
    background: radial-gradient(circle, #facc15 0, #f97316 45%, transparent 55%);
}

.icon-moon::before {
    content: "";
    position: absolute;
    inset: -4px;
    border-radius: inherit;
    box-shadow: -6px 0 0 0 currentColor;
    background: transparent;
}

.app-main {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr);
    gap: 20px;
}

.controls-grid {
    display: grid;
    grid-template-columns: 2.3fr 1.2fr;
    gap: 16px;
    align-items: start;
}

.card {
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border-subtle);
    box-shadow: var(--shadow-subtle);
    padding: 16px 18px 18px;
    backdrop-filter: blur(16px);
    transform-origin: center;
    transition: transform var(--transition-med), box-shadow var(--transition-med),
                border-color var(--transition-med), background var(--transition-med);
}

/* Explicit dark theme via data-theme */
[data-theme="dark"] .card {
    background: rgba(15, 23, 42, 0.92);
}

/* Optional: fallback to system dark theme when data-theme is not forced */
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .card {
        background: rgba(15, 23, 42, 0.92);
    }
}

.card:hover {
    transform: translateY(-1px);
    box-shadow: 0 20px 45px rgba(15, 23, 42, 0.22);
    border-color: var(--border-strong);
}

.card h2 {
    margin: 0 0 10px;
    font-size: 0.95rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--text-soft);
}

.task-creation {
    animation: slideDown 260ms ease-out both;
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px 16px;
}

.field {
    display: flex;
    flex-direction: column;
    gap: 4px;
    font-size: 0.8rem;
    color: var(--text-soft);
}

.field--full {
    grid-column: 1 / -1;
}

.field span {
    font-weight: 500;
}

.optional {
    font-weight: 400;
    opacity: 0.7;
}

input[type="text"],
input[type="search"],
input[type="date"],
select,
textarea {
    border-radius: 9px;
    border: 1px solid var(--border-subtle);
    background: rgba(248, 250, 252, 0.9);
    padding: 7px 10px;
    font: inherit;
    color: var(--text);
    outline: none;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast),
                background var(--transition-fast), transform var(--transition-fast);
}

textarea {
    resize: vertical;
}

input::placeholder,
textarea::placeholder {
    color: rgba(148, 163, 184, 0.9);
}

input:focus,
select:focus,
textarea:focus {
    border-color: rgba(37, 99, 235, 0.7);
    box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.4);
    background: #ffffff;
    transform: translateY(-0.5px);
}

.segmented-control {
    display: inline-flex;
    align-items: center;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border-subtle);
    padding: 2px;
    gap: 2px;
    background: rgba(15, 23, 42, 0.02);
}

.segmented-control__item {
    border: none;
    border-radius: var(--radius-pill);
    padding: 4px 10px;
    background: transparent;
    color: var(--text-soft);
    font-size: 0.8rem;
    cursor: pointer;
    transition: background var(--transition-fast), color var(--transition-fast),
                transform var(--transition-fast), box-shadow var(--transition-fast);
}

.segmented-control__item:hover {
    background: rgba(148, 163, 184, 0.12);
}

.segmented-control__item.is-active {
    background: var(--accent-soft);
    color: var(--accent-strong);
    box-shadow: 0 5px 14px rgba(37, 99, 235, 0.3);
    transform: translateY(-0.5px);
}

.form-actions {
    margin-top: 12px;
    display: flex;
    gap: 8px;
    justify-content: flex-end;
}

.button {
    border-radius: 999px;
    border: 1px solid transparent;
    padding: 7px 14px;
    font-size: 0.8rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    cursor: pointer;
    background: rgba(15, 23, 42, 0.04);
    color: var(--text);
    transition: background var(--transition-fast), color var(--transition-fast),
                border-color var(--transition-fast), transform var(--transition-fast),
                box-shadow var(--transition-fast);
}

.button.small {
    padding: 5px 10px;
    font-size: 0.75rem;
}

.button.primary {
    background: linear-gradient(120deg, var(--accent), var(--accent-strong));
    color: #eff6ff;
    border-color: rgba(15, 23, 42, 0.16);
    box-shadow: 0 14px 35px rgba(37, 99, 235, 0.7);
}

.button.primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 18px 45px rgba(37, 99, 235, 0.85);
}

.button.ghost {
    background: transparent;
    border-color: rgba(148, 163, 184, 0.5);
    color: var(--text-soft);
}

.button.ghost:hover {
    background: rgba(148, 163, 184, 0.1);
}

.filters-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 10px;
    align-items: end;
}

.filter-actions {
    display: flex;
    justify-content: flex-end;
}

.summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    flex-wrap: wrap;
}

.summary-item {
    min-width: 80px;
}

.summary-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-soft);
}

.summary-value {
    font-size: 1rem;
    font-weight: 600;
}

.task-list {
    margin-top: 4px;
}

.task-list__header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 8px;
}

.task-list__hint {
    font-size: 0.75rem;
    color: var(--text-soft);
}

.task-list__items {
    margin: 8px 0 0;
    padding: 0;
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.task {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 10px;
    align-items: flex-start;
    padding: 8px 10px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-subtle);
    background: var(--bg-elevated-soft);
    cursor: grab;
    transition: transform 140ms ease-out, box-shadow 140ms ease-out,
                border-color 160ms ease-out, background 160ms ease-out, opacity 160ms ease-out;
    animation: taskIn 180ms ease-out both;
}

.task[draggable="true"]:active {
    cursor: grabbing;
}

.task--dragging {
    opacity: 0.88;
    transform: scale(1.01);
    box-shadow: 0 16px 38px rgba(15, 23, 42, 0.28);
    border-style: dashed;
}

.task--placeholder {
    border-style: dashed;
    border-color: var(--accent);
    background: transparent;
}

.task-main {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.task-title-row {
    display: flex;
    align-items: baseline;
    gap: 6px;
}

.task-title {
    font-size: 0.9rem;
    font-weight: 550;
}

.task-meta-row {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    align-items: center;
}

.task-description {
    font-size: 0.8rem;
    color: var(--text-soft);
}

.badge {
    border-radius: 999px;
    padding: 2px 8px;
    font-size: 0.7rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    border: 1px solid transparent;
}

.badge-category.work {
    background: rgba(59, 130, 246, 0.12);
    color: #1d4ed8;
    border-color: rgba(37, 99, 235, 0.3);
}

.badge-category.home {
    background: rgba(37, 99, 235, 0.12);
    color: #2563eb;
    border-color: rgba(37, 99, 235, 0.35);
}

.badge-category.car {
    background: rgba(255, 215, 0, 0.12);
    color: #ffd700;
    border-color: rgba(255, 215, 0, 0.35);
}

.badge-category.personal {
    background: rgba(236, 72, 153, 0.12);
    color: #be185d;
    border-color: rgba(236, 72, 153, 0.35);
}

.badge-category.study {
    background: rgba(16, 185, 129, 0.16);
    color: #047857;
    border-color: rgba(16, 185, 129, 0.4);
}

.badge-category.health {
    background: rgba(34, 197, 94, 0.16);
    color: #15803d;
    border-color: rgba(34, 197, 94, 0.42);
}

.badge-category.hobby {
    background: rgba(236, 72, 153, 0.16);
    color: #be185d;
    border-color: rgba(236, 72, 153, 0.4);
}

.badge-category.other {
    background: rgba(148, 163, 184, 0.16);
    color: #475569;
    border-color: rgba(148, 163, 184, 0.45);
}

.badge-priority.low {
    background: rgba(148, 163, 184, 0.12);
    color: #64748b;
    border-color: rgba(148, 163, 184, 0.4);
}

.badge-priority.medium {
    background: rgba(249, 115, 22, 0.1);
    color: #c2410c;
    border-color: rgba(249, 115, 22, 0.4);
}

.badge-priority.high {
    background: rgba(239, 68, 68, 0.12);
    color: #b91c1c;
    border-color: rgba(239, 68, 68, 0.45);
}

.badge-due {
    background: rgba(59, 130, 246, 0.08);
    color: var(--text-soft);
    border-color: rgba(148, 163, 184, 0.4);
}

.badge-due.overdue {
    background: var(--danger-soft);
    color: var(--danger);
    border-color: rgba(239, 68, 68, 0.5);
}

.badge-due.today {
    background: rgba(234, 179, 8, 0.1);
    color: #b45309;
    border-color: rgba(234, 179, 8, 0.45);
}

.overdue-dot {
    width: 8px;
    height: 8px;
    border-radius: 999px;
    background: var(--danger);
    box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.18);
}

.task-actions {
    display: flex;
    align-items: center;
    gap: 4px;
}

.icon-button--soft {
    border-radius: 999px;
    border: 1px solid transparent;
    padding: 4px 6px;
    background: transparent;
    color: var(--text-soft);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition-fast), color var(--transition-fast),
                transform var(--transition-fast), border-color var(--transition-fast);
}

.icon-button--soft:hover {
    background: rgba(148, 163, 184, 0.14);
    color: var(--text);
    transform: translateY(-0.5px);
}

.icon-button--danger:hover {
    border-color: rgba(248, 113, 113, 0.8);
    color: var(--danger);
    background: var(--danger-soft);
}

.checkbox {
    width: 18px;
    height: 18px;
    border-radius: 7px;
    border: 1px solid rgba(148, 163, 184, 0.6);
    background: rgba(248, 250, 252, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background var(--transition-fast), border-color var(--transition-fast),
                transform var(--transition-fast), box-shadow var(--transition-fast);
}

.checkbox-inner {
    width: 12px;
    height: 12px;
    border-radius: 4px;
    background: transparent;
    transform: scale(0.5);
    opacity: 0;
    transition: transform var(--transition-fast), opacity var(--transition-fast),
                background var(--transition-fast);
}

.checkbox--checked {
    background: radial-gradient(circle at 20% 0, #eff6ff, var(--accent));
    border-color: rgba(37, 99, 235, 0.8);
    box-shadow: 0 9px 22px rgba(37, 99, 235, 0.7);
}

.checkbox--checked .checkbox-inner {
    opacity: 1;
    transform: scale(1);
    background: #eff6ff;
}

.task--completed .task-title {
    text-decoration: line-through;
    color: var(--text-soft);
}

.task--completed .task-description {
    opacity: 0.7;
}

.task--completed {
    opacity: 0.82;
}

.task--completed .badge-priority.high,
.task--completed .badge-priority.medium {
    filter: grayscale(0.4);
    opacity: 0.7;
}

.empty-state {
    padding: 18px 10px 4px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-soft);
}

.empty-state__sub {
    margin: 2px 0 0;
    font-size: 0.75rem;
}

.toast-container {
    position: fixed;
    right: 18px;
    bottom: 18px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    z-index: 50;
}

.toast {
    max-width: min(320px, 80vw);
    background: rgba(15, 23, 42, 0.96);
    color: #e5e7eb;
    border-radius: 999px;
    padding: 8px 14px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.8rem;
    box-shadow: 0 14px 35px rgba(15, 23, 42, 0.9);
    animation: toastIn 160ms ease-out forwards;
}

.toast--info {
    border: 1px solid rgba(96, 165, 250, 0.7);
}

.toast--danger {
    border: 1px solid rgba(248, 113, 113, 0.8);
}

.toast__dot {
    width: 10px;
    height: 10px;
    border-radius: 999px;
    background: #4ade80;
    box-shadow: 0 0 0 4px rgba(74, 222, 128, 0.2);
}

.toast__dot--danger {
    background: #f97373;
    box-shadow: 0 0 0 4px rgba(248, 113, 113, 0.22);
}

.toast__text {
    flex: 1;
}

.toast__close {
    border: none;
    background: transparent;
    color: inherit;
    cursor: pointer;
    opacity: 0.8;
    padding: 2px;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-6px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes taskIn {
    from {
        opacity: 0;
        transform: translateY(4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateY(5px) translateX(4px) scale(0.96);
    }
    to {
        opacity: 1;
        transform: translateY(0) translateX(0) scale(1);
    }
}

@keyframes toastOut {
    to {
        opacity: 0;
        transform: translateY(3px) scale(0.97);
    }
}

/* Responsive */

@media (max-width: 900px) {
    .app-shell {
        margin-top: 20px;
    }

    .controls-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .filters-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 720px) {
    .app-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .form-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .field--full {
        grid-column: 1 / -1;
    }

    .task {
        grid-template-columns: auto minmax(0, 1fr);
        grid-template-rows: auto auto;
    }

    .task-actions {
        grid-column: 2 / 3;
        justify-content: flex-end;
    }
}

@media (max-width: 520px) {
    .app-shell {
        margin: 14px auto 24px;
        padding-inline: 10px;
    }

    .card {
        padding-inline: 12px;
    }

    .filters-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .form-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .form-actions {
        justify-content: stretch;
    }

    .form-actions .button {
        flex: 1;
    }

    .task-list__header {
        flex-direction: column;
        align-items: flex-start;
    }
}